Nanotube based nanoelectromechanical device

ABSTRACT

A nanoelectromechanical device is provided. The nanoelectromechanical device includes a nanotube, a first contact, and a first actuator. The nanotube includes a first end, the first end supported by a first structure, a second end opposite the first end, and a first portion. The first actuator is configured to apply a first force to the nanotube, the first force causing the nanotube to buckle such that the first portion couples to the first contact.

BACKGROUND

The present application relates generally to the field ofnanoelectromechanical devices. More specifically, the present disclosurerelates to the field of using a nanotube to complete a circuit. Evenmore specifically, the present disclosure relates to the field ofmulti-state nanotube memory.

Nanotechnology is a rapidly developing field, which includes thedevelopment of nanostructures (e.g., nanotubes, fullerines, nanostrips,etc.) and nanoelectromechanical systems (NEMS) and devices. The smallscale of nanotechnology makes it an ideal match for electronics systems.For example, NEMS may be used in integrated circuits, switches, andmemory applications.

Conventional electronic switches and memory locations have binarystates, which provide 2^n possible combinations (n being the number ofmemory locations). Increasing the number of possible states increasesthe possible combinations to x^n (x being the number of states). Thisallows a much higher density of switching functions or memory data,leading to smaller and more compact designs.

SUMMARY

One embodiment relates to a nanoelectromechanical device. Thenanoelectromechanical device includes a nanotube, a first contact, and afirst actuator. The nanotube includes a first end, the first endsupported by a first structure, a second end opposite the first end, anda first portion. The first actuator is configured to apply a first forceto the nanotube, the first force causing the nanotube to buckle suchthat the first portion couples to the first contact.

Another embodiment relates to a nanoelectromechanical device having ananotube, a plurality of contacts comprising a first contact and asecond contact, a first electrode configured to apply a first force tothe nanotube, the first force acting in a first direction, and a secondelectrode configured to apply a second force to the nanotube, the secondforce acting in a second direction. The nanotube includes a first end,the first end supported by a first structure, a second end opposite thefirst end, and a first portion. The first portion is configured tocouple to one of the plurality of contacts depending on the ratio of thefirst force and the second force applied to the nanotube.

Another embodiment relates to a nanoelectromechanical device including ananotube extending from a first structure along an axis, the nanotubeincluding a first end supported by the first structure and a second endopposite the first end. The nanoelectromechanical device furtherincludes a plurality of contacts comprising a first contact and a secondcontact, a first actuator configured to rotate the nanotube about theaxis and to align the nanotube with one of the plurality of contacts,and a second actuator configured to deflect the nanotube such that thenanotube couples to the one of the plurality of contacts.

Another embodiment relates to a nanoelectromechanical device including ananotube having a first end supported by a first structure, a second endopposite the first end, a buckling location located between the firstend and the second end, a first segment extending from the first end tothe buckling location along a first axis, and a second segment extendingfrom the buckling location to the second end. The nanoelectromechanicaldevice further includes a plurality of contacts comprising a firstcontact and a second contact and a first actuator configured to rotatethe nanotube about the axis and to align the nanotube with one of theplurality of contacts.

Another embodiment relates to a nanoelectromechanical device including ananotube having a first end supported by a first structure and a secondend opposite the first end and supported by a second structure. Thenanoelectromechanical device further includes a plurality of contactslocated between the first structure and the second structure, a firstelectrode configured to apply a first force to the nanotube, the firstforce causing the nanotube to buckle such that a first portion of thenanotube couples to a first contact, and a second electrode configuredto apply a second force to the nanotube, the second force causing thenanotube to buckle such that a second portion of the nanotube couples toa second contact.

Another embodiment relates to a nanoelectromechanical device including ananotube having a first end supported by a first structure and a secondend disposed opposite the first end; a plurality of contacts spacedalong the length of a surface; and a first actuator configured to applya variable force to the nanotube, the variable force causing thenanotube to couple to the surface along a variable length, therebycoupling the nanotube to at least one of the plurality of contacts.

Another embodiment relates to a memory device including a nanotubehaving a first end supported by a first structure and a second endopposite the first end. The memory device further includes a firstmemory state, a second memory state in which the nanotube is elasticallydeformed, and a third memory state in which the nanotube is buckled.

Another embodiment relates to a method of closing an electrical circuit.The method includes providing a nanotube, providing a plurality ofcontacts, and causing the nanotube to buckle such that a portion of thenanotube couples to one of the plurality of contacts.

The foregoing is a summary and thus by necessity containssimplifications, generalizations and omissions of detail. Consequently,those skilled in the art will appreciate that the summary isillustrative only and is not intended to be in any way limiting. Otheraspects, inventive features, and advantages of the devices and/orprocesses described herein, as defined solely by the claims, will becomeapparent in the detailed description set forth herein and taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a nanoelectromechanical device, shownaccording to an exemplary embodiment.

FIGS. 2A-2D are schematic diagrams of the nanoelectromechanical deviceof FIG. 1, shown according to various embodiments.

FIGS. 3A-3B are schematic diagrams of a nanoelectromechanical device,shown according to another embodiment.

FIG. 4 is a schematic diagram of a nanoelectromechanical device, shownaccording to another embodiment.

FIGS. 5A-5B are schematic diagrams of a nanoelectromechanical device,shown according to another embodiment.

FIG. 6 is a schematic diagram of a nanoelectromechanical device, shownaccording to another embodiment.

FIGS. 7A-7B are schematic diagrams of a nanoelectromechanical device,shown according to another embodiment.

FIG. 8 is a schematic diagram of a nanoelectromechanical device, shownaccording to another embodiment.

FIGS. 9A-9C are schematic diagrams of a nanoelectromechanical device,shown according to another embodiment.

FIG. 10 is a schematic diagram of a nanoelectromechanical device, shownaccording to another embodiment.

FIG. 11 is a perspective view schematic diagram of ananoelectromechanical device, shown according to another embodiment.

FIG. 12 is a perspective view schematic diagram of ananoelectromechanical device, shown according to another embodiment.

FIG. 13 is a perspective view schematic diagram of ananoelectromechanical device, shown according to another embodiment.

FIGS. 14A-14B are schematic diagrams of a nanoelectromechanical device,shown according to various embodiments.

FIGS. 15A-15B are schematic diagrams of a memory device, shown accordingto an exemplary embodiment.

FIG. 16 is a schematic diagram of a memory device, shown according toanother embodiment.

FIG. 17 is a flowchart of a process for closing an electrical circuit,shown according to an exemplary embodiment.

FIG. 18 is a flowchart of a process for closing an electrical circuit,shown according to another embodiment.

FIG. 19 is a flowchart of a process for closing an electrical circuit,shown according to another embodiment.

DETAILED DESCRIPTION

Referring generally to the figures, a nanoelectromechanical device andcomponents thereof are shown according to exemplary embodiments. Thedevice generally includes a nanostructure (e.g., nanotube, nanostrip,fullerene, etc.) and one or more support structures (e.g., substrate).An actuator (e.g., an electrostatic electrode, piezoelectric actuator, amagnetostriction actuator, etc.) may be used to deflect the nanotubetowards a contact. Whether the actuator pulls or pushes the nanotube maydepend on the charge of the actuator relative to the charge on thenanotube, for example, in the case of an electrostatic electrode.According to various embodiments, the actuator may cause the nanotube toelastically deform or to buckle. Elastic deformation generally has alinear force versus deflection curve; however, when the nanostructurebuckles, it has a non-linear force versus deflection curve. Buckling maybe induced in the nanotube by exerting one or more forces on thenanotube. Buckling may further be induced or encouraged at a desiredlocation based on the location and direction of the force exerted uponthe nanotube or as a result of stress concentrators (e.g., stress riser,stress maximizer, etc.) acting on the nanotube. For example, defects(e.g., holes, extra atoms, etc.) may be formed in the nanotube structureat desired locations, thereby creating a weak point that is susceptibleto buckling. Mechanical stress concentrators (e.g., a sharp edgeproximate the nanotube), may encourage or induce buckling in aparticular location. Thus, buckling provides more control over thenanotube, and enables the nanotube to be moved into more configurationsthan just bending alone. Various combinations of actuators and contactsmay be configured to form switches or memory (e.g., volatile memory,non-volatile memory, random access memory (RAM), read only memory (ROM),programmable read only memory (PROM), erasable programmable read onlymemory (EPROM), etc.). For example, the nanotubes may be used to formsingle pole multiple throw switches or multi-state memory depending onthe number of contacts.

The described nanoelectromechanical device described herein has benefitswhich may be particularly useful in radiation sensitive environments,for example, satellites, earth-orbiting satellites, sensor technology,etc. Typical radiation shielding for integrated circuits uses ceramicpackaging. The devices described herein may provide a lower-cost,lower-weight approach to radiation shielding, while providing comparableperformance and reliability to traditional charge-storage memory havingradiation shielding. Other useful applications include lowintermodulation distortion radio frequency mixers and low level radiofrequency switches.

For purposes of this disclosure, the term coupled means the joining oftwo members directly or indirectly to one another. Such joining may bestationary in nature or moveable in nature and/or such joining may allowfor the flow of fluids, electricity, electrical signals, or other typesof signals or communication between the two members. Such joining may beachieved with the two members or the two members and any additionalintermediate members being integrally formed as a single unitary bodywith one another or with the two members or the two members and anyadditional intermediate members being attached to one another. Suchjoining may be permanent in nature or alternatively may be removable orreleasable in nature. References to “upward,” “downward,” “behind,”“inner,” “outer,” “right,” and “left” in this description are merelyused to identify the various elements as they are oriented in thefigures. These terms are not meant to limit the element which theydescribe, as the various elements may be oriented differently in variousapplications.

Referring to FIG. 1, a schematic diagram of a nanoelectromechanicaldevice 2 is shown according to an exemplary embodiment. The device 2generally includes a nanostructure (e.g., nanotube, nanostrip,fullerene, etc.), shown as nanotube 10, and one or more supportstructures 20 (e.g., substrate, wall, etc.). While the structure 20 isschematically shown as a simple anchoring structure, it is contemplatedthat in practice the structure 20 may include a plurality of layersincluding bit lines (e.g., right lines, word lines etc.), insulators,etc. The support structure 20 may be formed of any suitable material,for example, a silicon wafer substrate. As for the nanostructure, ananotube is preferably used because of its substantially uniformstructure and, therefore, known elastic, buckling, and failureproperties. Further, the cylindrical form of nanotubes enables them tobe self supporting and to be deflected in any number of directions.Nanotubes may be formed from a variety of materials including carbon,silicon, boron nitride, etc. Carbon nanotubes are preferably usedbecause they elastically deform and buckle at controllable levels andbecause they can reversibly buckle in more than one direction. Thenanotube 10 may be formed from any suitable method, including chemicalvapor deposition. According to some embodiments, the nanotube 10 may beformed in-situ or disposed on the support structure 20 so as to extendas a cantilever. According to other embodiments, the nanotube 10 may beformed or disposed between two support structures 20 a, 20 b (see, forexample, FIGS. 7-10). For example, the nanotube 10 may be formed acrossa trench 22.

An actuator 30 (e.g., an electrode, an electrostatic electrode, anode,cathode, etc.) may be used to deflect the nanotube 10 towards a contact32. Whether the actuator 30 pulls or pushes the nanotube 10 depends onthe charge of the actuator 30 relative to the charge on the nanotube 10.For example, if the actuator 30 and the nanotube 10 are both positivelyor negatively charged, then the actuator 30 will push or repel thenanotube 10. In contrast, if the actuator 30 and the nanotube 10 areoppositely charged, the actuator 30 will pull or attract the nanotube10. According to various embodiments, the actuator 30 may cause thenanotube 10 to elastically deform or to buckle.

The nanotube 10 includes a first end 12 and a second end 14 locatedopposite or distal from the first end 12. According to the embodimentshown, the nanotube 10 is coupled to and supported by the supportstructure 20 at the first end 12 and cantilevers outward therefrom. Thenanotube 10 further includes a portion 16 (e.g., region, section, area,etc.) configured to couple to the contact 32. Referring briefly to FIG.2D, the portion 16 may be disposed proximate the second end 14, shown asportion 16 a, or spaced apart from the first end 12 and the second end14, shown as portion 16 b. As shown, the actuator 30 may exert anattractive force on the nanotube 10 such that the nanotube 10 buckles ata first buckling location 18 a, and the portion 16 couples to thecontact 32 (as shown in dashed lines). According to various embodiments,coupling the portion 16 to the contact 32 may close or complete anelectrical circuit or set a memory state. Depending on the formation ofthe nanotube 10, the buckling of the nanotube 10 may be reversible orirreversible. For example, if the nanotube 10 has a relatively smalldiameter, the nanotube 10 is fairly resilient and will return to thenon-buckled state when the force from the actuator 30 is removed.However, if the nanotube 10 has a relatively large diameter, the buckledenergy state may be lower than the non-buckled energy state, and thenanotube 10 may require an additional treatment (e.g., an electricalforce, chemical immersion, heating, etc.) to return the non-buckledstate. According to one embodiment, the device 2 may be configured suchthat the nanotube 10 is held in a closed state by stiction between thenanotube 10 and the contact 32.

Referring to FIGS. 2A-2D, nanoelectromechanical devices 2 havingadditional actuators 30 and/or contacts 32 are shown according tovarious embodiments. The device 2 may include additional contacts 32 toform a multistate memory or multi-throw switch. To couple to a secondcontact 32 a second force may be exerted on the nanotube 10. As shown inFIG. 2A, the actuator 30 may be configured to apply a second orrepulsive force to the nanotube 10 that causes the nanotube 10 to coupleto a second contact 32 b. As shown in FIG. 2B, the device 2 includes asecond actuator 30 b, which may be configured to apply a secondattractive force to the nanotube 10 that causes the nanotube 10 tocouple to the second contact 32 b.

When coupling to different contacts 32, the nanotube 10 may buckle indifferent directions or different locations. As shown in FIGS. 2A, 2B,and 2D, the nanotube 10 may buckle at the same buckling location 18 a,but in a different direction that the first contact 32 a. As shown inFIG. 2C, the nanotube 10 may couple to a second contact 32 c by bucklingin the same direction as the first contact 32 a, but at a secondbuckling location 18 b. According to other embodiments, the nanotube 10may buckle at different locations and in different directions.

When coupling to different contacts 32, the same portion 16 of thenanotube 10 may couple to each of the contacts 32, or a differentportion 16 may couple to some of the contacts 32. As shown in FIGS.2A-2C, the same portion 16, shown as the tip of the nanotube 10, couplesto each of the contacts 32. As shown in FIG. 2D, a first portion 16 acouples to the first contact 32 a, but a second portion 16 b of thenanotube 10 couples to the second contact 32 d. Coupling to differentportions along the nanotube 10 may be useful or occur when differentcontacts 32 are disposed in different layers of a circuit board. Forexample, the first contact 32 a may be in a first layer and the secondcontact 32 d may be in a second layer of a circuit board.

Referring to FIGS. 3-6, various nanoelectromechanical devices 102, 202,302, and 402 are shown according to exemplary embodiments. The devicesinclude a plurality of actuators 130, 230, 330, 430 and a plurality ofcontacts 132, 232, 332, 432. As described above, the nanotube 110, 210,310, 410 may be pushed or pulled by an actuator to couple to a contact.For example, the devices 102, 202, 302, and 402 are shown toelectrostatically attract the nanotube; however, the actuators may applya repulsive force to the nanotube as described with respect to FIG. 2A.The devices may also be configured such that two or more actuatorsjointly exert forces upon the nanotube such that the nanotube deflectsin the direction of a resultant force, wherein the resultant force is afunction of the ratio of forces acting upon the nanotube. According tovarious embodiments, the nanotube may deflect by elastic deformation orbuckling, and the device 102, 202, 302, and 402 may be configured suchthat the nanotube remains coupled to a contact by stiction after theforces that caused the coupling have been removed. Briefly referring toFIGS. 7-10, while the devices 102, 202, 302, and 402 are shown as havingcantilevered nanotubes, it is contemplated that a second end 114, 214,314, 414 of the nanotube, located opposite the first end 112, 212, 312,412 maybe supported by a second structure 120 b, 220 b, 320 b, 420 bsuch that the nanotube 110, 210, 310,410 forms a bridge rather than acantilever.

Referring to FIGS. 3A and 3B, a nanoelectromechanical device 102 isshown according to an exemplary embodiment. FIG. 3A is a schematiccross-sectional elevational view of the device 102 shown in plan view inFIG. 3B. The nanotube 110 is shown disposed in a trench 122 (e.g., pit,well, etc.) such that nanotube 110 extends axially from a first end 112coupled to the floor 124 of the trench 122. The device 102 includes aplurality of actuators 130, shown as first through fourth actuators 130a-130 d, disposed in a first plurality of radial directions around thenanotube 110. As shown, the actuators 130 are evenly spacedcircumferentially around the nanotube 110. Each actuator 130 isconfigured to apply a force on the nanotube 110 in a particulardirection. For example, a first actuator 130 a is configured to apply afirst force to the nanotube 110, the first force acting in a firstdirection, the second actuator 130 b configured to apply a second forceto the nanotube 110, the second force acting in a second direction, andso on. The device 102 is further shown to include a plurality ofcontacts 132, shown as first through eighth contacts 132 a-132 h,disposed in a second plurality of radial directions around the nanotube110. The contacts 132 are shown to be evenly spaced circumferentiallyaround the nanotube.

According to the embodiment shown, when the first actuator 130 a actsupon the nanotube 110, the nanotube 110 couples to the first contact 132a, and when the second actuator 130 b acts upon the nanotube 110, thenanotube 110 couples to the second contact 132 b. However, when two ormore forces act upon the nanotube 110, the deflection of the nanotube110 is based on the ratio of forces and the generated resultant force.For example, when the first force and the second force of the first andsecond actuators 130 a, 130 b act upon the nanotube 110, the nanotube110 buckles in the direction of the resultant force and couples to athird contact 132 e, which is disposed in a third direction from thenanotube 110. According to one embodiment, the resultant force occurs atan angle of tangent (first force/second force) with respect to thenanotube 110.

According to the exemplary embodiment shown, the plurality of contacts132 are arranged in a ring around a vertically extending cantileverednanotube 110, and the actuators 130 are in the form of X and Ydeflection plates such that the nanotube 110 is deflected at an angle ofTAN(Vy/Vx). The device 102 is further shown to include a third actuator130 c, which is configured to apply a third force to the nanotube 110,the third force causing the nanotube 110 to buckle such that thenanotube 110 couples to a fourth contact 132 c. The third actuator 130 cmay be used in conjunction with the second actuator 130 b to couple thenanotube 110 to a fifth contact 132 f.

While even distribution of the contacts 132 and the actuators 130 aboutthe nanotube 110 simplifies the control of the nanotube 110, unevendistribution of the actuators 130 and the contacts 132 is contemplated.According to various other embodiments, the device 102 may comprise moreor fewer actuators 130 and contacts 132, and the actuators 130 and thecontacts 132 may or may not completely circumscribe the nanotube 110.

Referring to FIG. 4, a plan view of a nanoelectromechanical device 202is shown according to an exemplary embodiment. Like device 102, device202 includes an axially extending nanotube 210, a plurality of contacts232 located in a plurality of radial directions from the nanotube 210,and a plurality of actuators 230 located in a second plurality ofdirections from the nanotube 210. The device 202 is shown to include athird contact 232 e and a fourth contact 232 i between the firstactuator 230 a and the second actuator 230 b. Accordingly, the couplingof the nanotube 210 to a desired contact 232 i may be controlled by theratio of forces exerted upon the nanotube 210 by the actuators 230 a and230 b. The device 202 is further shown to include uneven distribution ofthe actuators 230 and the contacts 232.

Referring to FIGS. 5A and 5B, a nanoelectromechanical device 302 isshown according to an exemplary embodiment. FIG. 5A is a schematiccross-sectional elevational view of the device 302 shown in plan view inFIG. 5B. Like device 102, device 302 includes a nanotube 310 extendingaxially from a support structure 320, a plurality of contacts 332located in a plurality of radial directions from the nanotube 310, and aplurality of actuators 330 located in a second plurality of directionsfrom the nanotube 310. As shown, the plurality of contacts 332 areevenly interspaced between the plurality of actuators 330 such that noneof the contacts 332 are in the same direction from the nanotube 310 asan actuator 330. In operation, the nanotube may be coupled to a desiredcontact 332 d by controlling the ratio of forces exerted upon thenanotube 310 by a plurality of actuators 330, for example attractiveforces by the first and second actuators 330 a, 330 b. One advantage ofhaving all of the contacts 332 offset from the actuators 330 is that ifone of a pair of actuators 330 fails to exert force on the nanotube 310,the nanotube 310 will be attracted to the other of the pair where therewas no contact 332. Thus, the nanotube 310 would make no contact, ratherthan an errant contact. For example, in the embodiment shown, if thefirst actuator 330 a had failed, the nanotube 310 would be drawn to thesecond actuator 330 b, leaving the circuit open because the nanotube 310does not couple to a contact 332.

Referring to FIG. 6, a nanoelectromechanical device 402 is shownaccording to an exemplary embodiment. The device 402 is shown to includea nanotube 410 extending radially from a point 428 where the nanotube410 couples to the support structure 420; a plurality of contacts 432,shown as first through fourth contacts 432 a-432 d, which extend in aplurality of radial directions from the point 428; and a plurality ofactuators 430, shown as right and left actuators 430 a, 430 b. Accordingto one embodiment, the contacts 432 are arranged in a planar fan suchthat the plurality of radial directions defines a plane, that is, thecontacts 432 are located in a plane. According to the embodiment shown,the actuators 430 are coplanar with the contacts 432. The nanotube 410is shown to be in a first position extending in a first radialdirection, and the first and second actuators 430 a, 430 b are furthershown to be located along a secant line L-L that is substantiallyperpendicular to the first radial direction. According to the embodimentshown, the nanotube 410 is in the first position when no actuators 430are exerting force on the nanotube 410. In operation, the nanotube 410couples to a desired contact 432 based on the ratio of forces exerted onthe nanotube 410 by the left actuator 430 b and the right actuator 430a. According to various embodiments, the nanotube 410 may deflect byelastic deformation or buckling, and the device 410 may be configuredsuch that stiction between the nanotube 410 and a contact 432 maintainsa closed circuit after the coupling forces are removed.

Referring to FIGS. 7-10, various electromechanical devices 502, 602,702, and 802 are shown according to exemplary embodiments. The devicesshare similar characteristics to the device as described above; however,in these devices, the nanotube is not cantilevered, but is supported atthe second end to form a bridge, for example, over a trench. Accordingto various embodiments, supporting the nanotube at the second endconstrains movement of the nanotube, and may thereby reduce or eliminatethe need for stiction to maintain coupling between the nanotube and thecontact after the coupling forces are removed, thus facilitating designof bi-stable or multi-stable devices.

Referring specifically to FIGS. 7A and 7B, a device 502 includes ananotube 510 having a first end 512 coupled to a first structure 520 aand having a second end 514 located opposite the first end 512 andcoupled to a second structure 520 b. The nanotube 510 is shown to besuspended over a trench 522. The device 502 is further shown to includea first actuator 530 a configured to exert a first force in a firstdirection on the nanotube 510 and a second actuator 530 b configured toexert a second force in a second direction on the nanotube 510. As shownin FIG. 7A, when the first actuator 530 a exerts the first force uponthe nanotube 510, the nanotube 510 buckles in the first direction suchthat a portion 516 of the nanotube 510 couples to a first contact 532 a.As shown in FIG. 7B, when the second actuator 530 b exerts the secondforce upon the nanotube, the nanotube 510 buckles and a second directionsuch that the portion 516 of the nanotube 510 couples to a secondcontact 532 b. Referring briefly to FIG. 2A, one embodiment of thedevice 502 may include an actuator 530 which is configured to push orrepel the nanotube 510. Accordingly, the device 502 may only require oneactuator 530 to buckle the nanotube 510 in the first direction (e.g.,via attraction) and in the second direction (e.g., via repulsion).

Referring to FIG. 8, a device 602 includes a nanotube 610 suspended overa trench 622 between a first structure 620 a and a second structure 620b. The device 602 is shown to include first through third actuators 630a, 630 b, and 630 c, and first through third contacts 632 a, 632 b, and632 c. Each of the actuators 630 a, 630 b, 630 c is configured to exerta force on the nanotube 610 in a first, second, or third direction,respectively. As shown, the third actuator 630 c (illustrated as behind,or into the page from, the nanotube 610) is exerting a force in thethird direction such that the nanotube 610 buckles towards and couplesto the third contact 632 c. Briefly referring to FIGS. 3-5, it iscontemplated that two or more of the actuators 630 may jointly exertforces upon the nanotube 610 such that the nanotube 610 deflects in afourth direction corresponding to the direction of the resultant force,the direction of the resultant force being a function of the ratioforces exerted upon the nanotube 610 by the plurality of actuators 630.

Referring to FIGS. 9A-9C, a device 702 includes a nanotube 710 supportedbetween a first support structure 720 a and a second support structure720 b to form a bridge. A plurality of contacts 732 are spaced along thelength of the bridge. The device 702 includes a plurality of actuators730, each configured to exert a force on the nanotube 710. As shown, thedevice 702 is configured such that the actuators cause the nanotube 710to buckle in one or more locations, which causes the deflected nanotubeto assume a variety of shapes (e.g., saw-tooth, canoe, zigzag, etc.).The nanotube 710 may then be forced to couple to one or more desiredcontacts 732. As described above, with respect to FIG. 2A, an actuator730 may be configured to push or to pull the nanotube 710.

Referring specifically to FIG. 9A, the device 702 includes a firstactuator 730 a configured to exert a first force on the nanotube 710such that the nanotube 710 buckles at a first buckling location 718 a.Accordingly, the nanotube 710 assumes a saw-tooth shape facing right,and a first portion 716 a of the nanotube 710 couples to a first contact732 a. The device 702 further includes a second actuator 730 bconfigured to exert a second force on the nanotube 710 such that thenanotube 710 buckles at a second buckling location 718 b (shown indashed lines). In response, the nanotube 710 assumes a saw-tooth shapefacing left, and a second portion 716 b of the nanotube 710 couples to asecond contact 732 b.

Referring to FIGS. 9B and 9C, the device 702 may be configured such thattwo or more actuators 730 may exert forces upon the nanotube 710. Asshown in FIG. 9B, a first actuator 730 a and a second actuator 730 b mayboth exert attractive forces on the nanotube 710 such that the nanotube710 deflects to couple to the first and second contacts 732 a, 732 b. Asshown, the nanotube 710 may buckle and one or more locations to form acanoe shape. As shown in FIG. 9C, the first actuator 730 a and a thirdactuator 730 d may both exert attractive forces on the nanotube 710 suchthat the nanotube 710 deflects to couple to the first and third contacts732 a, 732 d. As shown, the nanotube 710 may buckle and one or morelocations to form a zigzag shape. According to the exemplary embodimentshown, the first and second contacts 732 a, 732 b are disposed along afirst line which extends substantially parallel to the nanotube 710, andthe third and fourth contacts 732 c, 732 d are disposed along a secondline which extends substantially parallel to the nanotube 710, the firstline and the second line being spaced apart from one another. Accordingto another embodiment, the first actuator 730 may apply an attractiveforce in a first direction, and the second actuator 730 b may apply arepulsive force in a second direction causing a rotational force a thirddirection which may result in the nanotube 710 contacting the thirdcontact 732 d as illustrated in FIG. 9C.

Referring to FIG. 10, a device 802 includes a nanotube 810 that ispre-buckled, for example, by compressive stresses exerted by a firstsupport structure 820 a and a second support structure 820 b. As shown,the nanotube 810 is supported at a first end 812 by a first supportstructure 820 a and is supported at a second end 814 by a second supportstructure 820 b. The nanotube 810 is supported to form a bridge, forexample, over a trench 822. A first actuator 830 a is configured toexert a force upon the nanotube 810 such that the buckle in the nanotube810 changes orientation or direction (e.g., pops, re-buckles, etc.).When the buckle changes orientation, the portion of the nanotube 810couples to a contact 832. According to an exemplary embodiment, thenanotube 810 is configured such that when the buckle changesorientation, the orientation of the buckle remains until another forceis exerted upon the nanotube 810, for example by a second actuator 830b. Accordingly, the nanotube 810 would remain coupled to the contact 832after the force exerted by the first contact 830 a is removed. Thistechnique may be usable in forming a non-volatile memory. Further, whenused in conjunction with the device as described above, a multistate,nonvolatile memory may be formed.

Referring to FIGS. 11-13, various nanoelectromechanical devices 902,1002, and 1102 are shown according to exemplary embodiments. The devicesare shown to include a plurality of actuators 930, 1030, 1130 and aplurality of contacts 932, 1032, 1132. The devices are configured suchthat at least one actuator deflects or rotates a nanotube 910, 1010,1110 in one axis and to align it with a desired contact. According toone embodiment, the nanotube 910, 1010 is configured to deflect in afirst direction from the axis, and at least one actuator 930, 1030 isconfigured to align the first direction with one of the plurality ofcontacts 932, 1032. According to another embodiment, the nanotube 910,1010, 1110 comprises a portion (e.g., 106) configured to couple to oneof the plurality of contacts 932, 1032, 1132, and at least one actuator930, 1030, 1130 is configured to align the first portion with one of theplurality of contacts 932, 1032, 1132, for example, such that when asecond actuator deflects the nanotube 910, 1010, the portion couples toone of the plurality of contacts 932, 1032, 1132. According to anotherembodiment, the nanotube 910, 1010 comprises a buckling location 918,1018 between the first end 912, 1012 and the second end 914, 1014, andat least one actuator 930, 1030 is configured to align the bucklinglocation 918, 1018 with one of the plurality of contacts 932, 1032,1132. At least one actuator 932, 1032 may deflect the nanotube in anorthogonal direction to couple the nanotube to the desired contact.

According to various embodiments, the nanotube may be buckled prior torotation, the nanotube may be rotated and then buckled, or the nanotubemay be permanently buckled. The actuators may be configured to applyattractive, repulsive, or rotative forces to the nanotube. The devices902, 1002, 1102 may be configured such that two or more actuatorsjointly exert forces upon the nanotube such that the nanotube deflectsin the direction of a resultant force, wherein the resultant force is afunction of the ratio of forces acting upon the nanotube. According tovarious embodiments, the devices 102, 202, 302, and 402 may beconfigured such that the nanotube remains coupled to a contact bystiction after the forces that caused the coupling have been removed ormay be configured such that the nanotube remains buckled, and thereforecoupled to the contact, until another force is applied to the nanotubeto return it to its un-buckled state. According to one embodiment, thedevice 902, 1002, 1102 may be configured such that buckling the nanotubedecouples the nanotube from a contact (i.e., breaks the contact) ratherthan couples the nanotube to the contact. Briefly referring to FIGS.7-10, it is further contemplated that the devices 902, 1002, 1102 may beconfigured as bridge nanotubes rather than cantilevered nanotubes asshown

Referring to FIG. 11, the device 902 is shown to include a nanotube 910having a first end 912 coupled to a support structure 920, a second end914 disposed opposite the first end 912, and a buckling location 918located between the first end 912 and the second end 914. A firstsegment 942 of the nanotube 910 extends from the first end 912 to thebuckling location 918, and a second segment 944 extends from thebuckling location 918 to the second end 914. The device 902 includes aplurality of actuators 930, shown as first through third actuators 930a-930 c, and a plurality of contacts 932, shown as first through fifthcontacts 932 a-932 e. The plurality of contacts 932 are shown to besubstantially circumferentially oriented around the nanotube 910. Inoperation, one of the actuators 930 may exert a force upon the nanotube910 causing the nanotube 910 to buckle (shown in dashed lines). Asshown, the second actuator 930 b causes the nanotube 910 to buckle in afirst direction and to buckle to a substantially right angle. Anotheractuator 930, for example first actuator 930 a, may then exert a secondforce upon the nanotube 910 such that the nanotube 910 rotates to coupleto the second contact 932 b or the first contact 932 a, depending on theratio forces between the first and second actuators 930. As the nanotube910 rotates, the first segment 942 may act as a torsional spring,thereby storing mechanical energy as the nanotube 910 is rotated aboutthe axis of the first segment 942. According to various embodiments, thenanotube 910 first buckles towards one of the other actuators 930 andthen rotates to another contact 932, for example, based on the closenessof the actuator 930 to the desired contact 932. This technique mayinduce lower rotational stresses on the nanotube 910; however, thistechnique may require a more complicated control system. According toanother embodiment, two or more actuators may jointly exert forces uponthe nanotube 910 such that the nanotube 910 directly buckles towards thedesired contact 932. For example, the first actuator 930 a and thesecond actuator 930 b may both exert forces upon the nanotube 910 suchthat the nanotube 910 buckles towards the second contact 932 b.

Referring to FIG. 12, the device 1002 includes a first actuator 1030 aconfigured to exert a first force on the nanotube 1010 causing thenanotube 1010 to rotate about a first axis and a second actuator 1030 bconfigured to exert a second force on the nanotube 1010 that causes thenanotube 1010 to buckle. The device 1002 further includes a plurality ofcontacts 1032, shown as first through third contacts 1032 a-1032 c. Inoperation, the first actuator 1030 a rotates the nanotube 1010 to alignthe nanotube 1010 with the desired contact 1032, and then the secondactuator 1030 b causes the nanotube 1010 to buckle such that a portion1016 of the nanotube 1010 couples to the desired contact 1032. As shown,a first portion 1016 a of the nanotube 1010 disposed between thebuckling location 1018 and the second end 1014 of the nanotube 1010couples to the second actuator 1032 b. According to other embodiments,one or more of the contacts 1032 may be located closer or further fromthe axis of rotation of the nanotube 1010 axis of rotation such thatwhen the nanotube 1010 buckles, a second portion 1016 b of the nanotube1010 couples to the selected contact 1032. According to the exemplaryembodiment shown, the plurality of contacts 1032 are arranged in asubstantially linear manner, such that the portion 1016 of the nanotube1010 that couples to a desired contact 1032 depends on the angle ofrotation of the nanotube 1010 and the distance of the contact 1032 fromthe axis of rotation. For example, the nanotube 1010 may rotate towardsthe first contact 1032 a, and then buckle such that a second portion1016 b of the nanotube 1010 disposed proximate the second end 1014 ofthe nanotube 1010 couples to the first contact 1032 a.

Referring to FIG. 13, the device 1102 is shown to include a nanotube1110 supported by a structure 1120. The device 1102 is further shown toinclude a plurality of contacts 1132 that form a substantiallycontinuous resistive element 1134 having a first output 1136 (e.g.,connector, connection, contact, input, etc.) and an actuator 1130configured to apply a force to the nanotube 1110 causing the nanotube1110 to rotate about the axis extending from the support structure 1120to a buckling location 1118. According to one embodiment, the resistancebetween the nanotube 1110 and the first output 1136 varies depending onwhere the nanotube 1110 couples to the resistive element 1134. Forexample, the resistance between the nanotube 1110 and the output 1136may be a function of how the nanotube 1110 is aligned relative to theresistive element 1134. In such an embodiment, the device 1102 may actas a variable resistor. According to another embodiment, the resistiveelement 1134 may have a second output 1138 (e.g., connector, contact,connection, input, etc.), and a voltage may be applied across theresistive element 1134 between the first output 1136 and the secondoutput 1138. When the nanotube 1110 couples to one of the plurality ofcontacts 1132, the nanotube 1110 divides the voltage across theresistive element where the nanotube 1110 couples to the resistiveelement 1134. For example, how the voltages are divided across theresistive element 1134 may depend on how the nanotube 1110 is alignedrelative to the resistive element 1134. In such an embodiment, thedevice 1102 may act as an adjustable voltage divider. According to theembodiment shown, the nanotube 1110 is permanently buckled at thebuckling location 1118.

Referring to FIGS. 14A and 14B, a nanoelectromechanical device 1202 isshown according to an exemplary embodiment. The device 1202 includes aplurality of contacts 1232, shown as first through third contacts 1232a-1232 c, spaced along the length of a surface 1228 and at least onevariable actuator 1230 configured to deflect the nanotube 1210 intocontact with the surface 1228 along a variable length thereby making 0,1, 2 . . . n connections. The nanotube 1210 is supported at a first end1212 by a first support structure 1220. As shown in the embodiment ofFIG. 14A, the actuator 1230 is configured to apply a variable force onthe nanotube 1210, thereby causing the nanotube 1210 to couple to thesurface 1228. A low force is shown to cause the nanotube 1210 to buckleat a first buckling location 1218 a and to couple to a first contact1232 a. A high force (shown in dashed lines) causes the nanotube 1210 tobuckle at a second buckling location 1218 b and to also couple to asecond contact 1232 b. The variable force may be controlled, forexample, by adjusting the frequency or amplitude of the signal sent tothe actuator 1230. The device 1202 may include additional contacts 1232(e.g., third contact 1232 c), and the nanotube 1210 may includeadditional buckling locations (e.g., third buckling location 1218 c).Accordingly, where the nanotube 1210 buckles and how many contacts 1232the nanotube 1210 couples to may be determined based on the variableforce generated by the actuator 1230. According to another embodiment,the contacts 1232 may be positioned on the surface 1228 such that a lowforce from the actuator 1230 causes the nanotube 1210 to couple to thesurface 1228 without coupling to one of the plurality of contacts 1232.Referring to the embodiment of FIG. 14B, a first actuator 1230 a may beconfigured to draw the nanotube 1210 into contact with the surface 1228,and a second actuator 1230 b may exert a variable force on the nanotube1210, thereby causing the nanotube 1210 to couple to the desired numberof contacts 1232. Briefly referring to FIGS. 9A-9C, other embodiments ofdevice 1202 may include a second support structure configured to supportthe second end 1214 of the nanotube 1210 such that the nanotube 1210forms a bridge.

Referring to FIGS. 15 and 16, memory devices 1302, 1402 are shownaccording to exemplary embodiments. The memory devices 1302, 1402 areshown to include a nanotube 1310, 1410 supported at a first end 1312,1412 by support structure 1320, 1420. Memory devices include a firstmemory state, a second memory state in which the nanotube is elasticallydeformed, and a third memory state in which the nanotube is buckled.According to various embodiments, the third memory state may bereversible or irreversible, erasable or permanent. For example, thebuckling deformation of the nanotube may be such that the nanotubereturns to an unbuckled state when the buckling force is removed. Inother examples, the nanotube may be forced back into the first or secondstate by applying another force (e.g., a repulsive electrostatic force,an attractive force from another actuator, a chemical bath, heating,etc.) to the nanotube. In yet other examples, the energy state of thenanotube structure may be sufficiently decreased during buckling thatthe nanotube structure cannot be unbuckled. According to one embodiment,the device may be configured such that the second memory state behavesas a random access memory (RAM) and the third memory state behaves as aread-only memory (ROM). In the ROM configuration, the nanotube may beconfigured such that is retained against the contact by stiction or bythe nature of the buckle in the nanotube. While the embodiments of FIGS.15 and 16 are shown to be cantilevered, it is contemplated that thememory devices may be configured such that the nanotube is a bridgesupported at both ends.

Referring specifically to FIG. 15A, the first state (shown in solidlines) is shown to be an off state in which the nanotube is not coupledto a contact 1332. Further, when the nanotube 1310 is in the firstmemory state the nanotube 1310 is not deflected. As shown, actuator 1330(e.g., a variable force actuator) is configured to exert a first (e.g.,low) force on the nanotube 1310 causing the nanotube 1310 to elasticallydeform (shown in dashed lines) such that the nanotube 1310 couples to acontact 1332. Referring to FIG. 15B, the actuator 1330 may further beconfigured to apply a second force (e.g., high) force on the nanotube1310 causing the nanotube 1310 to buckle (shown in dashed lines) suchthat the nanotube 1310 couples to the contact 1332. According to oneembodiment, the first force is less than the second force.

Referring to FIG. 16, the device 1402 is shown to include a firstcontact 1432 a, a second contact 1432 b, a first actuator 1430 a, and asecond actuator 1430 b. The device 1402 is configured such that thefirst actuator 1430 a exerts a first force on the nanotube 1410 so as tocause the nanotube 1410 to elastically deform such that a first portion1416 a of the nanotube 1410 couples to the first contact 1432 a. Thesecond actuator 1430 b exerts the second force on the nanotube 1410 suchthat the nanotube 1410 buckles at a buckling location 1418, and a secondportion 1416 b of the nanotube 1410 couples to the second contact 1432b.

Referring to FIG. 17, a flowchart of a process 1500 for closing anelectric circuit is shown, according to an exemplary embodiment. Process1500 is shown to include the steps of providing a nanotube (step 1502),providing a plurality of contacts (step 1504), and causing the nanotubeto buckle such that a portion of the nanotube couples to one of theplurality of contacts (step 1506).

Referring to FIG. 18, a flowchart of a process 1510 for closing electriccircuit is shown, according to an exemplary embodiment. Process 1510 isshown to include the steps of forming the nanotube as a cantilever (step1512), providing a plurality of contacts (step 1514), providing anactuator configured to apply a force to the nanotube, the force causingthe nanotube to buckle such that the portion that nanotube couples to afirst contact (step 1516), providing a second actuator configured toapply a second force to the nanotube, the second force causing thenanotube to buckle such that the nanotube couples to a second contact(step 1518), and applying the first force and the second force to thenanotube, the resultant force causing the nanotube to buckle such thatthe nanotube couples to a third contact (step 1520).

Referring to FIG. 19, a flowchart of a process 1530 for closing electriccircuit is shown, according to an exemplary embodiment. Process 1530 isshown to include the steps of providing a nanotube (step 1532),disposing the nanotube across a trench (step 1534), providing aplurality of contacts (step 1536) and exerting a electrostatic force onthe nanotube, the force causing the nanotube to buckle such that aportion of the nanotube couples to one of the plurality of contacts(step 1538).

The construction and arrangement of the devices and methods as shown inthe exemplary embodiments are illustrative only. Although only a fewembodiments have been described in detail, those skilled in the art whoreview this disclosure will readily appreciate that many modificationsare possible (e.g., variations in sizes, dimensions, structures, shapesand proportions of the various elements, values of parameters, mountingarrangements, use of materials, colors, orientations, etc.) withoutmaterially departing from the novel teachings and advantages of thesubject matter recited. For example, elements shown as integrally formedmay be constructed of multiple parts or elements. It should be notedthat the elements and assemblies may be constructed from any of a widevariety of materials that provide sufficient strength or durability, inany of a wide variety of colors, textures, and combinations.Additionally, in the subject description, the word “exemplary” is usedto mean serving as an example, instance or illustration. Any embodimentor design described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other embodiments ordesigns. Rather, use of the word exemplary is intended to presentconcepts in a concrete manner. Accordingly, all such modifications areintended to be included within the scope of the present inventions.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions, and arrangement of the preferredand other exemplary embodiments without departing from the scope of theappended claims.

The order or sequence of any process or method steps may be varied orre-sequenced according to alternative embodiments. Also, two or moresteps may be performed concurrently or with partial concurrence. Othersubstitutions, modifications, changes and omissions may be made in thedesign, operating configuration, and arrangement of the preferred andother exemplary embodiments without departing from the scope of theappended claims.

What is claimed is:
 1. A nanoelectromechanical device, comprising: ananotube comprising: a first end, the first end supported by a firststructure; a second end opposite the first end; a first portion; and asecond portion; a first contact; a second contact; a first actuatorconfigured to apply a first force to the nanotube, the first forcecausing the nanotube to buckle such that the first portion couples tothe first contact; and a second actuator configured to apply a secondforce to the nanotube, the second force causing the nanotube to bucklesuch that the second portion couples to the second contact.
 2. Thedevice of claim 1, wherein the first portion is disposed proximate thesecond end.
 3. The device of claim 1, wherein the first portion isspaced apart from the first end and the second end.
 4. The device ofclaim 1, wherein the first force is an electrostatic force.
 5. Thedevice of claim 1, wherein the first force causes the nanotube to buckleat a first buckling location, and the second force causes the nanotubeto buckle at a second buckling location.
 6. The device of claim 1,wherein the first force causes the nanotube to buckle in a firstdirection, and the second force causes the nanotube to buckle in asecond direction.
 7. The device of claim 1, wherein the second forcecauses the first portion of the nanotube to couple to the secondcontact.
 8. The device of claim 1, wherein the first force acts in afirst direction, and the second force acts in a second direction, andwherein the first force and the second force acting upon the nanotubecause the nanotube to buckle in a third direction.
 9. The device ofclaim 8 further comprising a third contact located in the thirddirection; wherein the first force and the second force acting upon thenanotube cause the nanotube to couple to the third contact.
 10. Thedevice of claim 1 further comprising: a third contact; and a thirdactuator configured to apply a third force to the nanotube, the thirdforce causing the nanotube to buckle such that the nanotube couples tothe third contact.
 11. The device of claim 1, wherein the second end issupported by a second structure.
 12. The device of claim 11, wherein thefirst force causes the nanotube to buckle at a first buckling location,and the second force causes the nanotube to buckle at a second bucklinglocation.
 13. The device of claim 11, wherein the first force causes thenanotube to buckle in a first direction, and the second force causes thenanotube to buckle in a second direction.
 14. The device of claim 11,wherein the second force causes the first portion of the nanotube tocouple to the second contact.
 15. The device of claim 11, wherein thefirst force acts in a first direction, and the second force acts in asecond direction, and wherein the first force and the second forceacting upon the nanotube cause the nanotube to buckle in a thirddirection.
 16. The device of claim 15 further comprising a third contactlocated in the third direction; wherein the first force and the secondforce acting upon the nanotube cause the nanotube to couple to the thirdcontact.
 17. The device of claim 1, wherein the first actuator isfurther configured to apply a third force to the nanotube, the thirdforce causing the nanotube to buckle such that the nanotube couples tothe second contact.
 18. The device of claim 17, wherein the third forcecauses the nanotube to buckle such that the second portion of thenanotube couples to the second contact.
 19. A nanoelectromechanicaldevice comprising; a nanotube comprising: a first end, the first endsupported by a first structure; a second end opposite the first end; afirst portion; and a second portion; a first contact; a second contact;and a first actuator configured to apply a first force to the nanotube,the first force causing the nanotube to buckle such that the firstportion couples to the first contact; wherein the first actuator isfurther configured to apply a second force to the nanotube, the secondforce causing the second portion of the nanotube to buckle such that thenanotube couples to the second contact.
 20. The device of claim 19,wherein the first force causes the nanotube to buckle at a firstbuckling location, and the second force causes the nanotube to buckle ata second buckling location.
 21. The device of claim 19, wherein thefirst force causes the nanotube to buckle in a first direction, and thesecond force causes the nanotube to buckle in a second direction. 22.The device of claim 19, wherein the second force causes the firstportion of the nanotube to couple to the second contact.
 23. The deviceof claim 19 further comprising: a third contact; and a second actuatorconfigured to apply a third force to the nanotube, the third forcecausing the nanotube to buckle such that the nanotube couples to thethird contact.
 24. A nanoelectromechanical device, comprising: ananotube comprising: a first end supported by a first structure; and asecond end opposite the first end and supported by a second structure;and a plurality of contacts located between the first structure and thesecond structure; a first electrode configured to apply a first force tothe nanotube, the first force causing the nanotube to buckle such that afirst portion of the nanotube couples to a first contact; and a secondelectrode configured to apply a second force to the nanotube, the secondforce causing the nanotube to buckle such that a second portion of thenanotube couples to a second contact.
 25. The device of claim 24,wherein the first structure and the second structure form a trenchtherebetween.
 26. The device of claim 24, wherein the first contact andthe second contact are disposed along a line which extends substantiallyparallel to the nanotube.
 27. The device of claim 26, wherein at leastone of the plurality of contacts is spaced apart from the line.
 28. Thedevice of claim 26 further comprising a third contact and a fourthcontact; wherein the third contact and the fourth contact are disposedalong a second line which extends substantially parallel to thenanotube.
 29. The device of claim 26 further comprising a thirdelectrode configured to apply a third force to the nanotube, the thirdforce causing the nanotube to buckle such that a portion of the nanotubecouples to a third contact.
 30. The device of claim 29, wherein thethird contact is spaced apart from the line.
 31. The device of claim 24,wherein the first electrode and second electrode are configured suchthat actuation of the first electrode and second electrode causes aresultant third force, the third force causing the nanotube to bucklesuch that a third portion of the nanotube couples to a third contact.32. The device of claim 24, wherein the device is configured such thatactuation of the first electrode and second electrode causes thenanotube to buckle such that the first portion of the nanotube couplesto the first contact and the second portion of the nanotube couples tothe second contact.
 33. The device of claim 24, wherein the first forceand the second force are electrostatic forces.
 34. The device of claim24, wherein the nanotube is compressed between the first structure andthe second structure.
 35. The device of claim 34, wherein thecompression causes a bulge between the first structure and the secondstructure.
 36. A nanoelectromechanical device, comprising: a nanotubecomprising: a first end supported by a first structure; a second endopposite the first end; and a plurality of contacts spaced along alength of a surface; and a first actuator configured to apply a variableforce to the nanotube, the variable force causing the nanotube to coupleto the surface along a variable length, thereby coupling the nanotube toat least one of the plurality of contacts.
 37. The device of claim 36,wherein the plurality of contacts are disposed along a line whichextends substantially parallel to the nanotube.
 38. The device of claim36, wherein the nanotube is cantilevered from the first structure. 39.The device of claim 36, wherein the second end is supported by a secondstructure.
 40. The device of claim 36, wherein the device is configuredsuch that a low force causes the nanotube to couple to the surfacewithout coupling to one of the plurality of contacts.
 41. The device ofclaim 36, wherein the device is configured such that with a high force,the nanotube couples to at least two contacts.
 42. The device of claim36 further comprising a second actuator configured to apply a secondforce to the nanotube; wherein the second actuator is configured todeflect the nanotube to the surface, and the first actuator isconfigured to deform the nanotube to couple along the length of thesurface.
 43. The device of claim 36, wherein the variable force causesthe nanotube to buckle.
 44. The device of claim 36, wherein the variableforce is an electrostatic force.
 45. A nanoelectromechanical device,comprising: a nanotube comprising: a first end, the first end supportedby a first structure; a second end opposite the first end; and a firstportion; a first contact; a second contact; a third contact; and a firstactuator configured to apply a first force to the nanotube, the firstforce causing the nanotube to buckle such that the first portion couplesto the first contact; a second actuator configured to apply a secondforce to the nanotube, the second force causing the nanotube to bucklesuch that the nanotube couples to the second contact; and a thirdactuator configured to apply a third force to the nanotube, the thirdforce causing the nanotube to buckle such that the nanotube couples tothe third contact.
 46. The device of claim 45, wherein the firstactuator is further configured to apply a fourth force to the nanotube,the fourth force causing the nanotube to buckle such that a secondportion of the nanotube couples to the second contact.
 47. The device ofclaim 45, wherein the second end is supported by a second structure.